Novel merocyanine dyes

ABSTRACT

NOVEL METHINE DYES ARE PROVIDED IN WHICH ONE TERMINAL CARBON ATOM OF THE METHINE CHAIN OF THE DYE HAS TWO GROUPS ATTACHED THERETO, SAID GGROUPS BEING SELECTED FROM A DIALKYLAMINO GROUP, A DIARYLAMINO GROUP, AN ALKYLARYLAMINO GROUP, A MORPHOLINO GROUP, A THIOMORPHOLINO GROUP AND A PIPERIDINO GROUP; AND, THE OTHER TERMINAL ATOM OF THE METHINE CHAIN OF SAID DYE IS ATTACHED TO A HETEROCYCLIC NUCLEUS OF THE TYPE USED IN METHINE DYES. THE PREPARATION OF SUCH DYES, AND PHOTOGRAPHIC EMULSIONS CONTAINING THEM, ARE ALSO PROVIDED HEREIN.

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United States Patent C) Not-248,296 InhCl. C091) 23/00 US. Cl. 260-2401 4 Claims ABSTRACT THE DISCLOSURE Novel methine, dyes are provided in which one terminal carbonatom ofthe methine chain of the dye has two groups attached thereto, said groups being selected from a dialkylamino group, a diarylamino group, an alkylarylamino group, a morpholino group, a thiomorpholino group and --a piperidino group; and, the other terminal atomof the methine chain of said dye is attached to a heterocyclic nucleus .of .the type used in methine dyes. The preparation of such dyes, and photographic emuls ions containing them, are also provided herein.

""Ihisis' 'a division of application Ser. No. 86,316 filed Nov. 2, 1970 now US. Pat. 3,672,905 issued June 27,

This invention relates to novel methine dyes, to new photographic'emulsions and elements containing these dyes, and to the preparationof these novel dyes and photographic materials.

It is oneeobject of this .invention to provide methine dyes derived from enamines.

Another object of this invention is to provide lightsensitivephotographic silver halide emulsions containing dyes derived from enamines as spectral sensitizers there- Still another object of this invention is to provide photographic'elements comprising a support having thereon at least one emulsion layer containing a dye of the invention-.0

Another object of this invention is to provide means for preparing these dyes.

Other objects of thisinvention will be apparent from this disclosure and the appended claims.

In accordance with this invention, novel methine dyes are provided .in-whichoneterminal carbon atom of the methine chain of the dye has two groups attached thereto, 'saidgroups being selected from a dialkylamino group, a diarylamino group, an alkylarylamino group, a morpholino. group, a thiomorpholino group and a piperidino group; and, the other terminal carbon atom of the methine chain of the dye is" attached to a heterocyclic nucleus of the type used in methine dyes.

As used herein and in the appended claims, the term methine dyes is used broadly as inclusive of dyes having the amidinium-ion system and the amidic system (as described' by Mees'and James, The Theory the PhotogrdphiwProcess, Third Edition, 1966, page 201 et seq.), and including cyanine and related dyes, such as hemicyanine dyesfmerocyanine dyes, oxamine dyes and the like.

Methine dyes in accordance with this invention, which can be derived from l-substituted amino-enamines, are excellent spectral sensitizers v for light-sensitive photo graphic silver halide emulsions, with maximum sensitivity peaks general1y in,. the range of about from 460 to 600 nm. Thus, these novel dyes typically sensitize in the blue to orange-fed region of the spectrum. In general, the novel dyes of this invention cause only very low fog levels in both fresh and-incubated emulsions, and the negative images produc'ed with' emulsions containing these dyes are clear and'sharp, and of excellent contrast.

Patented Sept. 3, 1974 Particularly useful methine dyes of this invention include those represented by the following formulas:

wherein n and represent positive integers of from 1 to 2 and 1 to 3 respectively. L represents a methine linkage, e.g., =CH, =C(CH =C(C H etc.; R represents an alkyl group, including substituted alkyl, (preff erably a lower alkyl containing from 1 to 4 carbon atoms), e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., and substituted alkyl groups (preferably a substituted lower alkyl con-' taining from 1 to 4 carbon atoms), such as hydroxyalkyl group, e.g., B-hydroxyethyl, w-hydroxybutyl, etc., an alk-' oxyalkyl group, e.g., fi-methoxyethyl, w-butoxybutyl, etc., a carboxyalkyl group, e.g., fl-carboxyethyl, w-carboxybu tyl, etc.; a sulfoalkyl group, e.g., fl-sulfoethyl, w-sulfobu tyl, etc., a sulfatoalkyl group, e.g., B-sulfatoethyl, w-sulfatobutyl, etc., an acyloxyalkyl group, e.g., B-acetoxyethyl, -acetoxypropyl, w-butyryloxybutyl, etc., an alkoxycarbonylalkyl group, e.g., fl-methoxycarbonylether, w-ethoxy carbonylbutyl, etc., or an aralkyl group, e.g., benzyl, phenethyl, etc., or any aryl group, e.g., phenyl, tolyl, naphthyl, methoxyphenyl, chlorophenyl, etc.; R R R and R taken independently each represents an alkyl group, including substituted alkyl (preferably a lower alkyl containing from 1 to 4 carbon atoms) e.g., the alkyl groups referred to above, or an aryl group, such as those mentioned above; R and R taken together, and R and R taken together, represent in each instance the non-metallic atoms necessary to complete a member selected from the group consisting of a morpholino group, a thiomorpholino group and a piperidino group; X represents an acid anion, e.g. chloride, bromide, iodide, perchlorate, sulfamate, p-toluenesulfonate, methyl sulfate, etc. and may be part of R when R, includes an acid group, such as a sulfoalkyl or a carboxyalkyl group, and the dye is in the form of its internal anhydride; Z represents the non-metallic atoms necessary to complete a 5- to 6-mernber heterocyclic nucleus of the type used in cyanine and hemicyanine dyes, which nucleus may contain a second hetero atom such as oxygen, sulfur, selenium or nitrogen, such as the following nuclei: 'a' thiazole nucleus, e.g., thiazole, 4-methylthiazole, 4-phen ylthiazole, S-methylthiazole, S-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4 (2 thienyl)thiazole, benzothiazole, 4 chlorobenzothiazole, 5 ChIOIObCIIZO. thiazole, 6 chlorobenzothiazole, 7 chlorobenzothiazole, 4-methylbenzothiazole, S-methylb'enzothi'azole, 6-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, 5 phenylbenzothiazole, 5 phenylbenzothiazole, 4; methoxybenzothiazole, 5 methoxybenzothiazole, 6 me thoxybenzothiazole, S-iodobenzothiazole, 6-iodobenzothia zole, 4 ethoxybenzothiazole, 5 ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6 dimethoxybenzothiazole, S, 6-dioxymethylenebenzothiazole, 5 hydroxybenzothia zole, 6 hydrobenzothiazole, naphtho[2,1-d]thiazole, naphtho [l,2-d]thiazole, S-methoxynaphtho [2,3-d]thiazole 5 eth-' oxynaphtho[2,3 d]thiaz0le, 8 methoXynaphtho[2,3-d]

for dyes where m is 2 or more, or of the formula for dyes where m is 1, with (2) an enamine of the formula (VII) s RIF-011: R4

wherein n, m, L, R R R R R X and Z are as previously defined, R represents an alkyl or aryl group, e.g., methyl, ethyl, phenyl, etc., and R represents hydrogen, alkyl or aryl groups, etc., in approximately equimolar proportions, in asolvent medium such as ethanol, preferably in the absence of basic condensation agents. The dyes are then separated from the reaction mixtures and purified by one or more recrystallizations from appropriatesolvents such as ethanol.

For the preparation of the novel dyes of Formula II above, a mixture comprisingv (1) a ketomethylene heterocyclic compound of the formula:

wherein L and Q are as previously defined, and R represents an alkyl or aryl group, e.g., methyl, ethyl, phenyl, etc., and (2) an enamine of above Formula VII, in solvents such as chloroform, dioxan or ethanol, is allowable to react, e.g., at temperatures from 0 to refluxing temperature and the resultingdye is purified, in generally similar manner as described immediately above. Another method for preparing a number of the novel methine dyes of Formula II above involves the use of the related immonium salts of the enamine derivatives of above Formula VII. For example, a ketomethylene heterocyclic compound of FormulaVIII above or of the formula:

wherein L, R and Q are as previously defined, is condensed with (2) an immonium salt of the enamine of formula VII, in approximately equimolar proportions in a solvent mediumsuch as pyridine,..and preferably in the presence of a basic condensation agent such as triethylamine. .The resulting .dye isisolated and purified by one or more,,recrystallizations from-appropriate solvent such as. ethanol/pyridine mixtures. a

The novel;complex methinedyes defined by Formulas III- and IVv above can be readily prepared from the methine dyes of Formula II, abovewhich contain a 2-thioxo substituent 0111116; ketomethylenev heterocyclic nucleus, such as for example a rhodanine nucleus, by alkylation with an alkyl ester followed by further condensation with an appropriateintermediate, for example, such as represented 6 by Formulas X, XI and XII, in the presence of a base such as triethylamine.

In the preparation of photographic emulsions, the new dyes of the invention are advantageously incorporated in the finished silver halide emulsion and should, of course, be uniformly distributed throughout the emulsion. The methods of incorporating dyes in emulsions are relatively simple and well known to those skilled in the art of emulsion making. For example, it is convenient to add the dyes from solutions in appropriate solvent, in which the solvent selected should have no deleterious effect on the ultimate light-sensitive materials. Methanol, isopropanol, pyridine, etc., alone or in combination have proven satisfactory as solvents for the majority of our new dyes. The type of silver halide emulsions that are sensitized with our dyes include any of those prepared with hydrophilic colloids that are known to be satisfactory for dispersing light sensitive silver halides, for example, emulsions prepared with hydrophilic colloids, such as, natural materials, e.g., gelatin, albumin, agar-agar, gum arabic, alg'mic, acid, etc., and synthetic hydrophilic resins, e.g., polyvinyl alcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetate, and the like.

The concentration of our new dyes in the emulsion can be widely varied, i.e., generally from about 5 to about mg. per liter of flowable emulsion. The specific concentration will vary according to the type of light-sensitive material in the emulsion and according to the effects desired. The most advantageous dye concentration for any given emulsion can be readily determined by making the tests and observations customarily used in the art of emulsion making. The dyes described herein can be used alone, in combination with each other or in combination with other spectral sensitizing dyes. The emulsions are coated to advantage on any of the support materials used for photographic elements, for example, paper, glass, cellulose acetate, cellulose acetate-propionate, cellulose nitrate, polystyrene, polyesters, polyamides, etc.

To prepare a gelatino-silver halide emulsion sensitized with one of the new dyes, the following procedure is satisfactory: A quantity of the dye is dissolved in a suitable solvent and a volume of this solution containing from 5 to 100 mg. of dye is slowly added to about 1000 cc. of a gelatino-silver halide emulsion. With most of the new dyes, 10 to 20 mg. of dye per liter of emulsion sufiice to produce the maximum sensitizing effect with the ordinary gelatino-silver halides including silver chloride, bromide, bromoiodide, chlorobromide, chlorobromoiodide, etc. emulsions. With fine-grain emulsions, which include most of the ordinary employed gelatino-silver chloride emulsions and the like, somewhat larger concentrations of dye may be necessary to secure optimum sensitizing effect. While the preceding has dealt with emulsions comprising gelatin, it will be understood that these remarks apply generally to any emulsions wherein part or all of the gelatin is substituted by another suitable hydrophilic colloid such as mentioned above.

The above statements are only illustrative and are not to be understood as limiting the invention in any sense, as it will be apparent that the new dyes can be incorporated by other methods in many of the photographic silver halide emulsions customarily employed in the art. For instance, the dyes can be incorporated by bathing a plate or film upon which an emulsion has been coated, in the solution of the dye in an appropritae solvent. Bathing methods, however, are not to be preferred ordinarily.

Photographic silver halide emulsions, such as those listed above, containing the sensitizing dyes of our invention can also contain such addenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), various gold compounds (e.g., potassium chloroaurate, auric trichloride, etc.) (see U.S. Pats. to W. D. Baldsiefen 2,540,085, granted Feb. 6, 1951; R. E. Damschroder 2,597,856, granted May 27, 1952, and H. C. Yutzy et a1. 2,597,915, granted May 27, 1952), various palladium compounds, such as palladium chloride (W. D. Baldsiefen U.S. 2,540,086, granted Feb. 6, 1951), potassium chloropalladate (R. E. Stauifer et al., U.S. 2,598,079, granted May 27, 1952), etc., or mixture of such sensitizers; antifoggants, such as ammonium chloroplatinate (A. P. H. Trivelli et a1. U.S. 2,566,245, granted Aug. 28, 1951), ammonium chloroplatinate (A. P. H. Trivelli et al. U.S. 2,566,263, granted Aug. 28, 1951), benzotriazole, nitrobenzimidazole, S-nitroindazole, benzidine, mercaptans, etc. (see Mees, The Theory of the Photographic Process, Macmillan Pub., 1942, page 460), or mixtures thereof; hardeners, such as formaldehyde (A. Miller U.S. 1,763,- 533, granted June 10, 1930), chrome alum (U.S. 1,763,- 533), glyoxal (J. Brunken U.S. 1,870,354, granted Aug. 9, 1932, dibromacrolein (0. Block et a1. British 406,750, accepted Mar. 8, 1934), etc.; color couplers, such as those described in I. F. Salminen et al. U.S. Pat. 2,423,730, granted July 7, 1947, Spence and Carroll U.S. Pat. 2,- 640,776, issued June 2, 1953, etc.; or mixtures of such addenda. Dispersing agents for color couplers, such as those set forth in U.S. patents to E. E. Jelley et al. 2,- 322,027 granted June 15, 1943, and L. D. Mannes et a1. 2,304,940, granted December 15, 1942, can also be employed in the above-described emulsions.

The following examples are included for a further understanding of this invention.

EXAMPLE 1 -(3',3'-Dipiperidinoallylidene)-3-ethoxycarbonylmethylrhodanine 1,1-Dipiperidinoethene (2 g.; .01M) and 3-ethoxycarbonylmethyl 5 ethoxymethylene rhodanine (2.8 g.; .01M) in chloroform (20 ml.) are allowed to stand in the cold for 1 hour. ePtroleum ether (200 ml.) is added and the product collected and recrystallized from methanol as orange needles, mp. 163 C., in 1.1 grams (29%) yield. Using generally similar procedures, as described above, related methine dyes 2 through 12 above can be prepared. The dye of the above example is tested in (1) a glatin chlorobromide emulsion and (2) in a silver bromoiodide emulsion of the type described by Trivelli and Smith, Phat. Journal, 79, 330 (1939). The dye, dissolved in a suitable solvent, is added to separate portions of the emulsions at the concentrations indicated. After digestion at 50 degrees C. for minutes, the emulsion is coated at a coverage of 432 mg. of silver/ft. on a cellulose acetate film support. A sample of the coatings is exposed on an Eastman 1B Sensitometer and to a wedge spectrograph, processed for three minutes at C. in a developer of the following composition:

Developer:

G. N-methyl-p-aminophenol sulfate 2.0 Sodium sulfite (anhydrous) 90.0 Hydroquinone 8.0 Sodium carbonate (monohydrate) 52.5 Potassium bromide 5.0

Water to make 1.0 liter.

and then fixed, washed and dried. The sensitizing values obtained are shown in the following Table 1.

TABLE 1 v Senslti- Sensization tiza- Dye 1 cone. Type of silver halide range tion Estima- (gJmole ag.) emulsion (nm.) (nm.) tion .10 Chlorobromide To 630 560 Excellent- .10 Bromoiodide To 610 550 Do.

These results indicate that the dye of the preceding example is an excellent spectral sensitizer for light-sensitive silver halide emulsions. Generally similar results are obtained with dyes 2 through 12 above.

The following example illustrates the preparation of enamine intermediates that are employed in the invention.

EXAMPLE '2 1,1-Di(piperidino)ethene This compound is prepared according to H. Baganz and L. Domaschke, Ber., 95, 2095 (1962). The corn pounds 1,1,-di(morpholino)ethene and l,1-di(thiomorpholino)ethene can be prepared in like. manner and substituted for 1,1-di(piperidino)ethene in the above examples to obtain useful methine dyes in accordance with this invention. i

It will be apparent from all of the foregoing, that still 1. A methine dye represented by the following formula:

wherein R R R and R taken independently, each represents a lower alkyl group. or an aryl .of 6 to 10 carbon atoms; R and R taken together, and R and R taken together, represent in each instance the non-metallic atoms necessary to complete a member selected from the group consisting of a morpholino group, a thiomorpholino group and a piperidino group; and, Q represents the non-metallic atoms necessary to complete a 5- or 6-membered ketomethylene heterocyclic nucleus selected from the group consisting of a 2-pyrazolin-5-one nucleus, an :isoxazolone nucleus, an oxindole nucleus, a 2,4,6 triketohexahydropyrimidine nucleus, a rhodanine nucleus, a 2(3H)-imidazo[l,2-a]pyridone nucleus, a thianaphthenone nucleus, a 2-thio-2,S-thiazolidinedione nucleus, a 2,4-thiazolidinedione nucleus, a thiazolidinone nucleus, a 2-thiazolin-4- one nucleus, a 2-imino-4-oxazolidinone nucleus, a 2,4-imidazolidinedione nucleus, a 2-thio-2,4-imidazolidinedione nucleus and a Z-imidazolin-S-one nucleus.

2. A methine dye as defined in Claim 1 wherein said R and R are taken together, and said R and R are taken together, and represent in each instance the non metallic atoms necessary to complete a'piperidino group;

3. The methine dye 5-(3',3'-dipiperidinoa1lylidene)-3- ethoxycarbonylmethyl rhodanine.

4. A methine dye according to Claim 1 wherein R R R R and R taken independently are aryl selected from the group consisting of phenyl, tolyl, naphthyl, methoxyphenyl and chlorophenyl.

References Cited UNITED STATES PATENTS 549,202 11/1942 England 260240.1

10 OTHER REFERENCES Lo, J. Am. Chem. Soc., vol. 80, pp. 3466-3468 (1958). Hamer, The Cyanine Dyes And Related Compounds, pp. 485 and 641, Interscience Publishers, N.Y. (1964).

Gruz et al., Zh. Obsch. Khirn., v01. 35, pp. 1639-1644 1965 JOHN D. RANDOLPH, Primary Examiner U.S. Cl. X.R.

96-127; 138, 140; 260-2408, 243 R, 247.5 R, 293.63, 306.8 R 

